Function getSectionOverlap

getSectionOverlap(section: RouteSpan, other: RouteSpan): RouteSpan | undefined
The stretch two sections of one route share, by point index.
Parameters
- section: RouteSpan
  A section of the route, of any type; a leg section only with its point indexes.
- other: RouteSpan
  Another section of the same route, likewise.
Returns RouteSpan | undefined
The shared stretch, or undefined when they share no segment, as two sections meeting at one point don't.
Example
```
const { country = [], toll = [] } = route.properties.sections;
const france = country.find((section) => section.countryCodeISO3 === 'FRA');
const tollsInFrance = france ? toll.filter((section) => getSectionOverlap(section, france)) : [];
```